1. Field of the Invention
Embodiments of the present invention relate to the field of collecting recyclable materials and, more particularly, to systems and methods for determining the composition and purity of a quantity of recyclable materials.
2. Background Description
To meet the growing problem of post-consumer goods disposal, many recyclable post-consumer goods are collected from the curbside and sent to a material recovery facility (MRF). MRFs are facilities where mixed recyclable materials are sorted and baled for sale, and generally serve as drop-off and gross-sorting (and limited processing) points for recyclable materials, so that sorted recyclable materials can be transported, for example, to a facility for subsequent processing.
Recyclable materials generally enter a MRF either in a single stream or dual stream. A single stream MRF may receive a mixture of commingled containers that may be made of glass, plastics, and/or metals, and fiber material that may include old news print (ONP) (e.g., newspaper and newspaper inserts), old corrugated paper (OCC), old telephone directories (OTD), old magazines (OMG), junk mail and/or office paper. A dual stream MRF generally has separate commingled container and fiber material streams.
Generally, recyclable materials arriving at MRFs can be sorted into individual material categories, such as glass, plastic, steel, aluminum, paper, cardboard, and the like. In addition, clear glass can be separated from colored glass, and plastics can be separated by type and color. Materials such as plastic, steel, aluminum, paper, and cardboard, can then be baled in a standard manner. Bales can be stored at an MRF until a buyer, such as a glass plant or paper recycling facility, purchases them.
While traditional MRFs typically utilize a dual stream configuration, the desire to reduce labor and other operational costs has been an impetus behind the trend toward single stream MRFs. However, sorted recyclable materials produced by single stream MRFs can have a higher contamination level than sorted recyclable materials from dual stream MRFs. Thus, for example, bales of sorted plastic from a single stream MRF may have an average purity of 95% by weight, whereas bales of sorted plastic from a dual stream MRF may have an average purity of 97% by weight.
In known systems, bale-specific information regarding purity is not generally ascertainable until you break open the bale. Accordingly, bales are typically sold based on physical accessibility of the bales within a MRF at the time of shipment. Lack of information pertaining to the purity of the bales can result in bales being rejected by the purchaser and returned to a MRF, or downgraded by the purchaser. This forces MRFs to absorb the cost associated with the returned bale(s), or to refund a portion of the sales price, particularly for bales emanating from single stream MRFs that generally have higher contamination rates than bales emanating from dual stream MRFs.
We have discovered that systems and methods for accurately and efficiently measuring the composition and purity of a bale and providing verifiable bale-specific information are needed. Such systems and methods can be used to ensure the purity of bales, increase customer satisfaction, and generate price premiums for the bales that are determined to have, for example, a higher than average level of purity.